The four major ventilation parameters of the ventilator are: tidal volume, pressure, flow, and time (including respiration frequency, inhalation-expiration ratio).

       1.Tidal volume: The tidal output must be greater than the human physiological tidal volume, the physiological tidal volume is 6-10 ml/kg, and the tidal output of the ventilator can reach 10-15 ml/kg, which is often 1~ of the physiological tidal volume. 2 times. It should be further adjusted according to chest fluctuations, auscultation of the air intake in both lungs, reference pressure gauges, and blood gas analysis.

       2.Breathing frequency: close to physiological breathing frequency. 40-50 times/min for newborns, 30-40 times/min for infants, 20-30 times/min for older children, and 16-20 times/min for adults. Tidal volume * Breathing rate = Ventilation per minute

       3.Inhalation-expiration ratio: generally 1:1.5~2, obstructive ventilatory disorders can be adjusted to 1:3 or longer exhalation time, restrictive ventilatory disorders can be adjusted to 1:1.

       4.Pressure: Generally refers to the peak airway pressure (pip). When lung compliance is normal, the peak inspiratory pressure is generally 10-20 cm H2O, mild lung disease: 20-25 cm H2O; moderate: 25-30 Millimeter water column; Severity: more than 30 cm water column, up to 60 cm water column in rds and pulmonary hemorrhage. But generally below 30, the pressure of newborns is 5 cm water column lower than the above-mentioned pressure.

       5.peep：Children who use ippv generally give peep 2~3 cm of water column, which is in line with the physiological condition. When severe ventilation disorders (rds, pulmonary edema, pulmonary hemorrhage) need to increase peep, generally 4~10 cm of water column, and it can be reached in severe cases. 15 or even 20 cm of water column above. When the oxygen concentration exceeds 60% (fio2 is greater than 0.6), if the partial pressure of arterial oxygen is still below 80 mmHg, peep should be increased until the partial pressure of arterial oxygen exceeds 80 mmHg. Every increase or decrease of peep by 1 to 2 mm of water column will have a great impact on blood oxygen. This effect can appear within a few minutes. The reduction of peep should be done gradually, and attention should be paid to monitoring changes in blood oxygen. The peep value can be read from the end-expiratory position of the pointer of the second pressure gauge. (It is better to have a special display)

       6.Flow rate: at least twice the ventilation volume per minute, generally 4-10 liters/min.